The invention provides a filter device, an RF front-end device and a wireless communication device. The filter device comprises a substrate, at least one resonance device, a passive device and a connector, wherein the at least one resonance device has a first side and a second side opposite to the first side, the substrate is located on the first side, and the passive device is located on the second side. The at least one resonance device is connected to the passive device through the connector. The RF filter device formed by integrating the resonance device (such as an SAW resonance device or a BAW resonance device) and the passive device (such as an IPD) in one die can broaden the passband width, has a high out-of-band rejection, and occupies less space in an RF front-end chip.

A radio frequency module includes a mount board, an acoustic wave filter, a temperature sensor, and a correction circuit. The mount board has a first principal surface and a second principal surface on opposite sides of the mount board. The acoustic wave filter is disposed on the first principal surface side of the mount board. The temperature sensor is disposed on the second principal surface side of the mount board. The correction circuit corrects a pass band of the acoustic wave filter in accordance with a temperature measured by the temperature sensor.

An acoustic wave device including a support substrate, a piezoelectric layer provided over the support substrate, at least one pair of comb-shaped electrodes disposed on the piezoelectric layer, each of the at least one pair of comb-shaped electrodes including electrode fingers, a temperature compensation film interposed between the support substrate and the piezoelectric layer, the temperature compensation film having a temperature coefficient of elastic constant opposite in sign to a temperature coefficient of elastic constant of the piezoelectric layer; and an insulating layer interposed between the support substrate and the temperature compensation film, a first surface of the insulating layer having first protruding portions and/or first recessed portions, a second surface of the insulating layer having second protruding portions and/or second recessed portions, the first surface being closer to the support substrate, the second surface being closer to the temperature compensation film.

Guided Surface Acoustic Wave (SAW) devices with improved quartz orientations are disclosed. A guided SAW device includes a quartz carrier substrate, a piezoelectric layer on a surface of the quartz carrier substrate, and at least one interdigitated transducer on a surface of the piezoelectric layer opposite the quartz carrier substrate. The quartz carrier substrate includes an orientation that provides improved performance parameters for the SAW device, including electromechanical coupling factor, resonator quality factor, temperature coefficient of frequency, and delta temperature coefficient of frequency.

A surface acoustic wave device includes a piezoelectric substrate including principal surfaces and an IDT electrode on a first principal surface side of the principal surfaces, and the first principal surface is a polarization positive potential surface of the piezoelectric substrate.

An acoustic wave device includes a mounting substrate, and an acoustic wave element chip. The mounting substrate includes a first major surface with an electrode land thereon, and a second major surface facing the first major surface. The acoustic wave element chip includes a piezoelectric substrate including a major surface, and a functional electrode and a bump located over the major surface of the piezoelectric substrate. The bump is joined to the electrode land. A heat radiation pattern is located over the first major surface of the mounting substrate and located within a region facing the functional electrode of the acoustic wave element chip. The heat radiation pattern is connected to an internal layer portion of the mounting substrate between the first and second major surfaces, and not electrically connected to the electrode land on the first major surface.

Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a mass loading strip. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can have a sidewall that is tapered inwardly from a bottom side of the mass loading strip to a top side of the mass loading strip. The top side can be shorter than the bottom side.

An elastic wave device includes first mass adding films provided on a first dielectric film to overlap with first and second electrodes fingers of an IDT electrode when seen from above, extend in a direction in which the first and second electrode fingers extend, and are provided in a center region, and second and third mass adding films that are provided on the first dielectric film and are provided in first and second edge regions, respectively, and a portion of which overlap with at least one of the first and second electrode fingers when seen from above. Dimensions of the second and third mass adding films along an elastic wave propagation direction are larger than a dimension of the first mass adding films along the elastic wave propagation direction.

A multiplexer includes a filter located between a common terminal and an individual terminal, and a filter that is located between the common terminal and an individual terminal and that has a pass band whose frequency is lower than the pass band of the filter. The filter includes serial arm resonators provided on the first path connecting the common terminal to the individual terminal. Each of the serial arm resonators includes a piezoelectric substrate and an IDT electrode which use leaky waves as principal acoustic waves. The occurrence frequency of the Rayleigh wave response of the serial arm resonator is different from that of the serial arm resonator.

A high-order mode surface acoustic wave device includes a piezoelectric substrate (11) formed from a LiTaO.sub.3 or LiNbO.sub.3 crystal and an interdigital transducer electrode (12) embedded in a surface of the piezoelectric substrate (11) to use a surface acoustic wave in a high-order mode. Further, the high-order mode surface acoustic wave device may include a film (13) or substrate stacked on the piezoelectric substrate (11), and may include a support substrate (11) and/or a multi-layer film (15) provided in contact with a surface opposite to the surface of the piezoelectric substrate (11) on which the interdigital transducer electrode (12) is provided. The high-order mode surface acoustic wave device may achieve good characteristics and maintain a sufficient mechanical strength even in a high frequency band of 3.8 GHz or greater.